To... that no vehicle shall have the ability to drive off and do a "herbie goes bananas" AND explode into flame unchecked (for want of better wording)...For this rule I believe the "fit criterion" is that no vehicle shall have the ability to drive off and do a "herbie goes bananas"...
So this might be better wording and maybe would work for both cars and bikes...
"A DRIVER/RIDER SHALL BE IN CONTROL OF THE RACE VEHICLE AND ALL DRIVER CONTROLLED SAFETY MECHANISMS ANY TIME THE ENGINE IS RUNNING"
I am not sure though if this would allow someone to sit beside a bike in the shade with a lanyard attached but I would image that having some mechanism to switch of the vehicle would constitute being in control (since the lanyard is the alternative to the shutoff switch).